Liquid-conductor heater



June 24, 1930.

R O T N E V W Marsha Whan/fs. BY

M. w. HANKS LIQUID CONDUCTOR HEATER Filed March 16. 1929 ATTORNEY Patented June 24, 1930 IAIBSHALL W. BANKS, MADISON; WISCONSIN LIQUID-CONDUGI'OB HEATER Application filed March", 1929. Serial No. 347,547.

My invention relates to liquid-conductor heaters in which heat is generated by passage of electric current through a body of liquid in which spaced electrodes are sub- 5 merged.

-tate cleaning the heater parts which may become coated with such solid materials as may be precipitated thereon during normal use.

I Ieretofore, it has been the usual, and sup posedly necessary, practice to employ con ducting terminal members having metallic contact with the submerged electrodes in order to ensur'e'proper current flow from the one to the other through the liquid.

Patent N 0. 1,683,071 granted to Hankscraft Company September 4, 1928, on an application filed by Max Mason and myse f, discloses, in Figs/3 and 4 of its drawings, a structure in which the electrical contact for one of the electrodes comprises a terminal stud 53 to which is screwed the electrode 12. With this construction, it is necessary that the electrode 42 make metallic electrical contact with terminal stud 53. Should metallic electrical contact fail, through dirt or corrosion of the electrode or terminal at point of contact, the device would fail to function as intended even though the contacts were wet. There would be a small leakage of current through the liquid between the terminal stud and the electrode, but this would be entirely inade uateto permit sufiicient current to pass t rough the circuit to operate the de vice. Agaln, Figs. 12, 13 and 14 show structures where the removable electrodes rest on terminal studs 97 and 118. For the function of these structures, metallic contact between the terminal studs and electrodes is imperative. If either the terminal stud or the electrode becomes dirty or oxidized at point of contact so that metallic electric, connection fails, the device will not function as intended.

In Patent No. 1,683,069, also granted to Hankscraft Company September 4, 1928, upon an application filed jointl by Max Mason and myself, actual metal ic cont-act must be made between the removable electrode member and the terminal stud to ensure suuicient current flow to produce the desired results.

In this case, actual metallic contact must be made between the removable electrode and the terminal stud to ensure sufficient current flow to produce the desired results. If the terminal stud is dirty at the point of contact, or the removable electrode itself is dirty, by reason of the collection of lime or sedlment, actual metallic contact of the electrode with the terminal stud will fail. Under this condition, it will be necessary to clean both the stud and the removable electrode in order to reestablish adequate contact for ensuring a sufficient flow of current to make the electrodes function as intended. However, if the contacts are dirty, so that metallic connection is not established, and if water or other conducting liquid is poured in, there will be a small amount of current flow, but not of sufficient volume to make the device function as intended.

It will thus be seen that electrodes of liquid-conductor heaters have heretofore been connected to an electric circuit by metallic means, in order that such heaters might properly perform their functions.

My present invention relates specifically to means for electrically connecting the circuit to one or both electrodes by using what I shall call liquid contact. Fundamentally, it involves the principle of so increasing the area of the electrode and that part of a fixed contact terminal located adjacent to it that the leakage through the exposed wet surface of such enlarged parts will be suflicient to ensure adequate flow of current, even though the electrode and the fixed terminal are not in actual metallic contact.

Referring to the drawing,

Figure 1 is a vertical sectional view of a liquid-conductor heater which illustrates the principle of my invention;

Figure 2 is a lan view of the heater shownin Fig. 1, t e removable member of the structure being omitted Fig. 3 is a vertical sectional view of one embodiment of my invention;

Fig. 4 is a plan view of the device shown in Fig. 3, the removable electrode member being omitted;

Fig. 5 is a view, similar to Fig. 3, of another embodiment of my invention, and

' Fig. 6 is a plan view of the device shown in Fig. 5, the removable electrode member being omitted.

Referring specifically to Fi 1, the electrode container 14 may be 0 any suitable insulating material, such as porcelain, bakelite, etc., or a metal receptacle havin a lining of insulating material. 1 an 2 are electrodes of suitable conductin material connected to the electric circuit through posts or studs 12 and 12. 3 is a removable plate which may or may not be perforated and is held, by gravity, in a position above electrodes 1 and 2, upon a ledge 13 of the container 14.

When a liquid conductor, such'as water, is poured into the insulating container 14, electrical connection is established between electrodes 1 and 2 throu h the liquid and the intermediate remova le plate 3. In this case, the circuit is from one nor ductor of circuit 15 to electrode 1 through the liquid to plate 3 and from plate 3, through the liquid to electrode2, and to the other side of the circuit 15.

When liquid is poured into the container and current is turned on, the water will become heated by reason of the current passing through it. Heating is approximately the same at both electrodes 1 and 2, so long as the water is not boiling. The

' moment the water starts to boil, the active bubbling will shift either to electrode 1 or to electrode 2 but bubbling seldom occurs over both at the same time. This phenomena of the water preferring not to boil on both sides at the same time, but to remain static on the one or the other side, discloses the possibility of using the water itself for adequateelectrical contact for one or both electrodes, since evaporation is effected only by the formation of bubbles and, therefore, the portion of the liquid in which no bubbles are produced is merely a part of the electric circuit, i. e., in effect, a part of each of the adjacent metal electrodes.

While the form shown in Fig. 1 is operative, the electrodes require more area and more water than would be the case were the design refined, as shown in Figs. 3 to 5.

In Fig. 3, the contact terminal 4 is of sufficient area to ensure adequate electric-current flow to the electrode 6, when the surface is wet, even though metallic contact is not established. The water, making liquid contact between the contact terminal 4 and electrode 6, will not boil to such extent as to interfere with the practical How of current, for the reason that the area is excessive and the energy-loss low because of the thin film of water and excessive surface. This is equivalent to raising electrode 1 in Fig. 1 to a point where it almost touches the plate 3.

Another point of decided advanta e in the arrangement shown in Fig. 3, is the act that the contact terminal 4 is a complete ring. With an arrangement of this character, and the ring connected to the grounded side of the electric circuit, it is obvious that there would be little opportunity of receiving a shock from the moistsurface of the container 14. This is a decided advantage in liquid-conductor heaters where they are used in homes or in any service where the hand mi ht come in contact with the wet surface urin the operation of the device.

In Fig. 5, the terminal contact buttons 7, 8 and 9 may be considered as sections of ring 4 shown in Fig. 3, as they are electrically connected together to form multiple contact-either liquid or metallicbetween as a portion of'their surface is given over to make adequate electrical connection with the terminal contact through the liquid film. The result of this arran ement permits sufficient current to flow to eat or vaporize the liquid between the electrodes, even though they are not in metallic contact with their terminals.

I have shown the electrode as a perforated metal late but an unperforated plate may be utilized and, whether perforated or unperforated and whatever its form in other respects, it may be made of any conducting material.

It is also to be understood that heaters embodying my invention may be employed for various purposes, such as evaporating a measured quantity of water or other vaporizable liquid, or for merely heating a body of liquidwhether vaporizable or not-t0 a desired temperature for ultimate use per se or for imparting its heat, as a cooking agent, to other articles of food or drink.

ios

Such modifications of form, dimensions and materials may be made as fall within the scope of the appended claims.

I cla1m as m invention:

1. In a liqui -conductor heater nation with a receptacle for a bod of liquid, and spaced terminal electrodes 0 relatively large surface area located therein, of a plate electrode above said terminal electrodes in liquid-conductorrelation thereto to cooperind-conductor heater, the combination wit a receptaclefor a body of liquid, and. substantially parallel terminal electrodes therein of large surface area, of a perforated .plate electrode located adjacent to said terminal electrodes in liquid-conductor relation thereto to cooperate with the body of liquid in conducting heat generating electric current between them. 4

4. In a liquid-conductor heater, the 001m bination with a receptable for liquid, andspaced conducting terminal electrodes adjacent to the bottom thereof, of a late electrode loosely supported above sai terminal electrodes in liquid-conductor relation thereto to cooperate with the body of liquid in which they are submerged to constitute a heat-generating conducting path for electric current.

In testimony whereof, I have hereunto subscribed my name this 12 day of March,

. MARSHALL W. HANKS,

the combi- 

